The present invention relates to an attachment for a light unit.
U.S. Pat. No. 5,017,770 and GB-B-2183889 (Sigalov) disclose interactive light-to-MIDI equipment comprising a support assembly and a plurality of light units. Said support assembly comprises a structure consisting of a plurality of telescopic arms which are pivoted on a central hub. Said hub may be suspended from a ceiling or other superstructure, and the arms may be manipulated such that they extend radially outwardly of the hub. Said light units are mounted on the arms, and each comprises a lamp that is adapted emit a beam of light generally downwardly, and an integrant light sensing element that is positioned in front of the lamp in the beam. Said light sensing element is shielded from direct light from the lamp, but is adapted to detect light that is retroreflected back towards the light unit.
Said light sensing element may comprise a photoresistive diode which is connected to an analogue to digital pulse generator. Said pulse generator converts the analogue output of the detector to a digital xe2x80x9ctriggerxe2x80x9d signal which is MIDI compatible. In turn, the output of the pulse generator can be connected to a MIDI interface, and this can be connected to sound generator or other MIDI device of kinds well known to those skilled in the art. The MIDI interface can be set up to transmit a MIDI instruction to the sound generator or other MIDI-control device in response to a digital xe2x80x9ctriggerxe2x80x9d pulse from the pulse generator.
In use, a user such, for example, as a musician or dancer operates the equipment by wearing or carrying on part of his or her body a piece of rectroreflective material. When the user cuts a beam of light from one of the light units with the rectroreflective material, then part of the beam is retroreflected back towards the light unit, thus activating the light sensing element. Alternatively the system can be operated in an xe2x80x9cinverse modexe2x80x9d in which a piece of retroreflective material is disposed at a fixed, remote location in front of each light unit. Light from the light unit is thus constantly reflected back towards the light unit by the retroreflective material, and is incident on the light sensing element. In this case the user does not need to be equipped with retroreflective material, but will cause a discontinuity in the output of the light sensing element simply by interrupting the beam of light with a non-reflecting member such, for example, as part of his or her body, thus shading the fixed retroreflective material from the beam. Such interruption in the output of the light sensing element is converted by the pulse generator into a control signal.
Most commonly, the equipment will be used to drive a sound generator such, for example, as a music synthesizer or drum computer. The output of each respective light unit may be used to generate a different note or sound. U.S. Pat. No. 5,017,770 and GB-B-2183889 disclose that the outputs of a group of light units may be connected through appropriate electronic circuitry to provide control over a different MIDI parameter in addition to the digital trigger signal. Thus, the speed at which two juxtaposed beams are cut by a user may, for example, be used to provide volume control. U.S. Pat. No. 507,770 and GB-B-2183889 also disclose that the equipment may be used to control non-sound devices such as other lighting devices and devices which can move objects, release smoke or odours, provide temperature control or release stage snow, stage rain or balloons or the like. The light emitted by the lamp of each light unit may be visible or invisible, although for most music applications, it is envisaged that each lamp will generate a different colour of visible light.
U.S. Pat. No. 5,017,770 and GB-B-2,183,889 thus disclose an integrated light-to-MIDI system that comprises light units, light sensing elements and electronic equipment for converting the output of the light sensing elements to MIDI instruction code. Such equipment works well, but is self-contained and therefore difficult to integrate with pre-existing equipment.
According to the present invention there is provided an attachment for a light unit, which attachment comprises light-detecting means, adapted to generate an output signal corresponding to the intensity of light incident thereon, and adjustable attaching means for removably attaching said attachment to a light unit such that the light-detecting means are positioned within a beam of light emitted by the light unit in use and are adapted to detect light that is directed towards said light unit, said attaching means being adjustable to allow the attachment to be selectively fitted to a range of differently sized light units.
The invention thus provides an attachment which can be fitted to a pre-existing light unit to convert the light unit into an interactive light-operated controller. It is envisaged that said adjustable attaching means may be adapted to attach the attachment to a wide variety of different kinds of light units without restriction. In particular, the attaching means may be adapted for connecting the light sensing means to known kinds of theatre lighting, including ellipsoidals, pars, fresnels and pinspots.
Preferably, said light sensing means comprises a light sensing element and shielding means for shielding the light sensing element from direct light emitted by the light unit and/or ambient light, so as to avoid false positive readings. Said shielding means may comprise an opaque, elongate housing that is arranged substantially co-axially with the beam when the attachment is fitted to a light unit, which housing is closed at one end that is disposed closest to the light unit and is open at its other end, the light sensing element being disposed within the housing. In some embodiments, said housing may comprise a tube that is closed at said one end, with the light sensing element being mounted within the tube. Said housing serves to ensure that the only retroreflected light impinges on the light sensing element to provide stable operation of the attachment. Operation of the light sensing element may be further enhanced by the provision of lens means for concentrating said retroreflected light onto the light sensing element.
Said attaching means may be adapted such that, when fitted to a light unit, said light sensing means is positioned generally centrally within the beam emitted by the light unit. In some embodiments, said attaching means may comprise adjustable positioning means for adjusting the position of the light sensing means relative to the light unit.
It will be appreciated that the present invention is not limited to any particular form or configuration of attaching means. The invention embraces a wide variety of different kinds of attaching means suitable for attaching the light sensing means to a wide variety of different kinds of theatre lighting as mentioned above. Furthermore, said attaching means may comprise mechanical fastening means for fastening the attachment to a light unit, or alternatively other kinds of releasable fastening means may be employed such, for example, as magnetic fasteners and adhesive pads. In some embodiments, the attaching means may be adapted simply to allow the attachment to be placed on the light unit or a part connected thereto such that the light unit is retained in position by gravity and optionally one or more stops to prevent lateral movement.
In some embodiments of the invention, said attachment may further comprise pulse generating means for converting the output signal of the light sensing means into a digital or analogue signal, particularly a control signal. Typically, said signal may be a MIDI compatible signal.
Said attachment may further comprise signal transmitting means for transmitting the output signal of said light detecting means to a suitable remote receiver. Said transmitting means may comprise electromagnetic wave transmitting means for transmitting said control signal to a remote receiver on an electromagnetic carrier wave. In some particularly preferred embodiments of the invention, said transmitting means may be adapted to provide an infra-red carrier signal for carrying the control signal. Of course, the invention does not preclude the possibility that the output of the light sensing means or pulse generating means may be hard-wired into a suitable receiver.
The attachment of the invention may be provided with appropriate power leads for connecting the light sensing means and optional pulse generating means to a source for electrical power. However, in some embodiments, the attachment may further comprise photovoltaic generator means to provide electrical power to the attachment, which photovoltaic generator means are positioned in the beam of light emitted by the light unit in use, when the attachment is attached to said light unit. Said photovoltaic generator may comprise at least one photovoltaic cell.
Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.